Environmental enhancement of US biomass crop technologies: Research results to date

The U.S. continues efforts to develop genetically superior short-rotation woody crops (hybrid poplar and willow) and herbaceous crops (switchgrass). These biomass crops can provide multiple environmental benefits as well as energy and fiber. This paper focuses on results of site-specific studies that are quantifying the environmental potential and ramifications of converting agricultural croplands to biomass crop production. At research-scales, no differences have been found in erosion and movement of nutrients from annual row crops, switchgrass, and tree crops with and without a cover crop in the initial year of establishment. Research- and watershed-scale studies on different soil types, in different regions, and to match tree species with specific site characteristics and management regimes will help determine whether research-scale results can be used to predict effects at larger scales and to identify best management practices to minimize environmental effects while maximizing yields. Studies in different regions of the U.S. are evaluating the habitat value of biomass crops compared to agricultural row crops, grasslands, or natural forests. Results to date from both research- and larger-scale plantings show that SRWCs support greater bird diversity than row crops, but less diversity than natural forests. Switchgrass plantings extended habitat for grasslands birds compared to row crops. Surveys on industrial tree crop plantings in the south-eastern U.S. are addressing the relationship between site characteristics (planting acreage, species, landscape context, and age of plantings) and breeding bird use. The environmental studies of water and soil quality and wildlife diversity are being used to identify management strategies for biomass crops to increase productivity while increasing agricultural sustainability. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.